A mathematical model of plant single-tracheid resistance calculation is established to investigate the relationship between the tracheid structure and the inner diameter and electrical resistivity of plant tracheid.The water flow in plant tracheid with different torus-margo bordered pit structure was simulated of different torus-margo bordered pit structure is carried out by using the low Reynolds number k-ε model for the torus-margo bordered pit resistance. The results show that the parameters such as pit diameter, pit depth, diameter of torus, and porosity of margo are the main factors affecting the resistivity and inner diameter of tracheid. It is found that with the increase of the pit depth, the resistivity of the pit depth of 6 μm is reduced by 18.57% compared with the pit depth of 3 μm, and the inner diameter of the tracheid increases by 23.43%. With the increase of the porosity of margo, the resistivity of the porosity of margo of 66.7% is reduced by 9.80% compared with the porosity of margo of 16.7%, and the inner diameter of the tracheid increases by 10.65%. As the pit diameter increases, the resistivity of the pit diameter of 16 μm is reduced by 9.21% compared with the pit diameter of 10 μm, and the inner diameter of the tracheid increases by 10.54%. As the diameter of torus increases, the resistivity of the diameter of torus of 4 μm is increased by 8.76% compared with the diameter of torus of 2.5 μm, and the inner diameter of the tracheid decreases by 8.14%. The change in the pit structure leads to the difference in the aspect ratio of the tracheids, and the calculated ratio is (95∶1)-(70∶1). In the case of a certain resistance of the pit, the proportion between the pit resistance and tracheid flow length resistance decreases as the tracheid flow length increases, when the flow length is two-thirds of the length of the tracheid, the proportion is 0.997, and the type of pit does not affect the ratio between the pit resistance and tracheid flow length resistance.